An Enantiomerically Pure 1,5,7-Trimethyl-3-azabicyclo[3.3.1]nonan-2-one as ¹H NMR Shift Reagent for the ee Determination of Chiral Lactams, Quinolones, and Oxazolidinones

The chiral lactam 1 (or its enantiomer ent-1) was shown to be an effective ¹H NMR shift reagent for the ee determination of chiral lactams, quinolones, and oxazolidinones. It was successfully employed in many cases in which a detection of enantiomers by chromatographic methods failed. The method was extended to a broader range of simple substrates bearing a lactam moiety to evaluate its scope. The NH signals of the substrate enantiomers showed the strongest separation and were used for ¹H NMR integration. In most cases, compound 1 (1.5 equiv; 0.06 M solution) induced a baseline separation of the NH signals and it can consequently be regarded as a generally applicable shift reagent for chiral products with a lactam moiety.